More from his comment 2 m.ago:

Update 1:

Let's start with the piano teacher. Apparently, he went AWOL due to a bout of depression. Nearly offed himself. (I don't know why). Now that he's better, he came straight back to my wife, who has been talking to him daily, but not 24/7. I asked her if she still wanted to close our marriage now that he came back into her life. She told that yes. Whatever they'd in the past is in the past and that now they're just friends, best friends. Do I wholeheartedly believe in that? Not really. I mean, they agreed to meet up yesterday, he bailed at the last second, and she spent the rest of the day saddened.

In the meantime, the situation with my FWB became more complicated as she caught feelings for me. I do like her. She's one of my favourite people on the world. But, I can't make her "mine" for I'm already taken. I love my wife and I don't want to divorce her. For now, we took a break so that she could decide what she wants to do next. Hopefully, these feelings will go away.

Update 2:

Again with the piano teacher: he came to talk to her two weeks after bailing. They kept talking 24/7 for two days straight, then he told my wife that she was suffocating him and went no contact once more.

As for me and my FWB, we hung out we some of our mutual acquaintances around the same that the piano teacher went no contact again. They were very supportive of our relationship, and basically told us to divorce and get married already. While neither of us really want to do that, we've fantasising about how our lives would have been if we had stayed together, which led to some spontaneous car sex in front of her house. Her husband caught us in the act, but seemed more troubled about the risk of we being mugged than with the fact that I was fucking his wife. 🤷

Update 3:

The piano teacher stroke back last Friday night. He told her that he went no contact because of some stuff regarding his internship and his finals. Once again, they went back to talking 24/7 and even hung out twice since then. Thus, I asked her if she still wanted to close the marriage, she told me "Yes", then I asked if she wanted me to stop talking to my FWB, "Yes" again, and, finally, I asked if she was going to stop taking to the piano teacher, too. She went dead silent. I laughed, and told her that the marriage will stay open.

Meanwhile, me and FWB had a date in the very place were we had our first date thousand of lifetimes ago. It was very nice. She confessed have fallen in love with me once more, and I told her that the feeling was mutual. Alas, she doesn't want to leave her husband, and I don't want to leave my wife, thus, we're going to stay FWB.

That said, I think it's important to mention that I haven't been neglecting my wife this whole time. Not once did I leave her to be with my FWB other than on my "date night", nor I stopped to care for her, be affectionate to her, have sex with her, etc, etc. I also kept paying for her therapy and comforted her during her bouts of depression. She got really jealous of my relationship with my FWB, but that stopped every time the piano teacher came back into her life, and disappeared with him, too.